Subsequent Event (Details) (4.75% Notes, USD $) In Millions, unless otherwise specified			0 Months Ended	3 Months Ended
Dec. 31, 2012	Dec. 31, 2003	Jan. 31, 2013 Subsequent event	Mar. 31, 2013 Subsequent event Forecast
Subsequent event
Long-term debt			$ 143.8
Interest rate (as a percent)	4.75%	4.75%	4.75%
Redemption price as percentage of principal amount			100.00%
Unamortized deferred financing costs				$ 0.9

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration